Science: The Star Betelgeuse

Stargazing is often dull, uneventful stuff.  Sure, once in awhile you might catch something creeping across some tiny sliver of the sky, but you don’t have to tune every night to see how hot Venus is or who’s orbiting Uranus now.  The heavens are just very, very samey, far too static on our lives’ time scale to be exciting.

What isn’t static though, unless it’s broken, is television: our technological replacement for the nighttime sky that we turn to when we want some excitement.  So why not try bouncing some star light off that blackest of TV mirrors, reality television, and see if we can find some entertaining trash inside? The red supergiant Betelgeuse for example has a seething, vacuous screen presence that befouls the local airwaves, and its anticipated public meltdown is sure to be a real spectacle – perfect for a tell-all expose.  Of course, this trashy nonsense will rot your mind, but we’re not here to judge, just to to observe and enjoy. Let he who is without guilty pleasures cast the first episode.

Betelgeuse’s program broadcasts here in North America from about late August to May, if you’re willing to chase it across the nighttime schedule.  For the past several hundred (if not thousand) seasons, Betelgeuse has established itself as the ninth-brightest watchable star, but is still losing out to Rigel as the brightest in Orion’s entourage.  Betelgeuse would be the brightest star on screen, but we only get to see about 13% of it’s electromagnetic footage with our own eyes. That said, Betelgeuse still flaunts what it’s got at about seven to ten thousand times brighter than our low-charisma Sun, and is a youthful ten to twelve million years compared to our Sun’s frumpy middle-aged four billion-plus.

Looks-obsessed TV can’t help but shame Betelgeuse for carrying twenty times the mass of our Sun and having a waist that’s, like, a thousand times bigger though; for an example, look no further than the scolding chart below.  See how the distance from the Sun to the Earth is a svelte size 1? Betelgeuse all by itself is what, a size 4? If the Sun got voted off the solar system and Betelgeuse took its place, Betelgeuse couldn’t hope to fit into the Asteroid Belt and would probably crowd out Jupiter too.


Although boring, our Sun has managed to remain traditionally telegenic thanks to its few-million smoothing ‘granules’; these are convection cells inside a star that cycle heat from inside of the star, each one simmering away like unresolved personal issues.  Older stars like Betelgeuse may have fewer issues, only a dozen granules or so, but they’re much bigger ones, ripe for being blown out of proportion on reality TV.  Perhaps that’s why Betelgeuse is desperately losing weight by shedding about one earth’s worth of mass a year through it’s solar wind – you can see that right there on the chart, it’s not even trying to hide it!  Our Sun may be tight, fit and toned, but it’s lack of charisma just makes for ho-hum watching compared to Betelgeuse’s hot mess that’s nearing the end of its fifteen minutes.

See, red supergiants like Betelgeuse quickly eliminate themselves by having over-baked their hydrogen cores.  All stars start off with this pretty common souffle recipe:

  1. Theme ingredient: hydrogen.
  2. Let the hydrogen’s gravity draw in more hydrogen until clumps start to form, which will draw in still more.
  3. Crush that gravity-bound hydrogen under its own weight and pressure until the hydrogen atoms in the core fuse together into helium atoms, releasing a bunch of watchable heat and energy on the screen.
  4. Keep that heat steady so that the atoms bounce off each other like celebrity D-listers locked up in a house together, rather than just collapsing further inward; a fallen souffle is bad news (keep this step in mind as it will return on an upcoming episode).
  5. Bake for millions or billions of years, depending on the serving size.

The star core’s oven keeps this going until time’s up and all the hydrogen is gone, baked into helium.  Betelgeuse, like any other red supergiant, now faces the new challenge of baking its helium into one heavier element after another, rushing through carbon to oxygen then neon, magnesium, and silicon more and more quickly – all terrible recipes for a star’s figure too, by the way, which explains Betelgeuse’s current state.  But all these recipe substitutions come to a stop with an iron souffle, a star can’t bake iron into anything else, so the oven starts to cool down and the souffle is about to fall.

Remember step 4 from the souffle recipe above?  No more fusion means no more heat, which is when the gravity of the predicament overwhelms a red supergiant star and leads to a TMZ-ready Type II supernova.  When Betelgeuse finally gives up, we’ll see a brief paparazzi flash before its spotlight shines as brightly as the full moon for a few weeks, even during the day.  Betelgeuse might even become the highest rated thing in the heavens for over a year (except for our stale old Sun, again); one source of celebrity gossip speculates it might even be bright enough to unwatchable, hurting your eyes just to look at it.

Despite what some societal scolds might predict, we viewers will be able to enjoy the show from the safety of our couches, cozy beneath the blankets of our Sun’s solar wind, Earth’s magnetic field and the ozone layer.  Betelgeuse isn’t going to bring down Western civilization with a gamma-ray burst of charisma, and its just too remote for us to worry about the x-rays, ultraviolet radiation, or ejected material from its cancellation.  After Betelgeuse’s on-air crack up has run its course, it will no doubt be reduced to some cheesy neutron star spin-off show, or drop out of show business altogether, leaving a black hole on the broadcast schedule – probably just the spin-off show because it’s not a big enough star to leave that much of an impression.

But when will we get to see this breathtaking finale?  Will it air tomorrow night, or is it being saved for a later season?  No one knows when this train is going to wreck. Tabloid rags may breathlessly tease that this special episode is due any night now, but more than likely not, we’ll have to sit through another hundred thousand tension-building seasons, maybe even a million.

Which is a real drag.  Why isn’t there anything good on TV when I get to watch it?!  I guess astronomy just doesn’t fit our television time slot after all, and this reality TV metaphor I’ve mixed and mangled wasn’t a good way to look at Betelgeuse, but then again, reality TV isn’t good TV, either.  Still, every time I flip past the Orion program on my nighttime screen, I’m always going to check in on Betelgeuse, hoping I might to catch the moment it becomes the biggest flash in the pan we’ve ever seen.